1. Technical Field of the Invention
The present invention relates to a bus bar wiring plate body for an electric coupling box used for coupling an electric system within a vehicle such as an automobile etc. and, more particularly, relates to the configuration of a bus bar wiring plate body for an electric coupling box which increases the insulating resistance between bus bar members disposed within the electric coupling box to make it possible to improve and withstand voltage and reduce leak current.
2. Related Art
As shown in FIG. 7, a related electric coupling box such as a junction block (J/B), a relay box etc. used for electric wiring within a vehicle such as an automobile etc. is provided with a bus bar wiring plate 1 in which a plurality of bus bar members 3 wired along the surface of an insulating substrate 2 are formed in a manner that respective tab-shaped terminals 7 are protruded upwarded and downward from both opposite surfaces of the insulating substrate 2. The related electric coupling box is provided with a rear cover 4 for housing the bus bar wiring plate 1, a front cover 6 on which connector housings 6a to 6c are disposed as relays, a fuse, an electronic circuit unit etc. are protrusively provided, and a waterproof cover 9 capable of covering the front cover.
In particular, as shown in FIG. 8, the bus bar wiring plate 1 is arranged in a manner that, in order to wire the bus bar members 3 along the surface of the insulating substrate 2, respective ribs 2A for positioning and increasing the insulating resistance are protrusively provided among the respective bus bar members 3 on the insulating substrate 2.
However, according to the related bus bar wiring plate 1, as the power supply voltage (battery voltage) of a vehicle has been increased from 12V to 36V, the conventional ribs"" 2A insulating resistance between the bus bar members 3 decreases, and so leak current flows. When this leak current flows, there arise problems in that a failure caused by signal leakage may occur, and that an unexpected failure likely occurs due to the carbonization of the insulating substrate 2 caused by the heat.
In order to eliminate such problems, such countermeasures are considered that the transversal width of each of the ribs 2A is made larger as shown in FIG. 9 or that the height of each of the ribs 2A is made higher as shown in FIG. 10. However, each of such countermeasures has a problem that the size of the electric coupling box itself becomes larger and the packaging density within the electric coupling box reduces.
Further, although the bus bar members 3 are wired within groove portions formed by the respective ribs 2A on the surface of the insulating substrate 2, since both the bus bar members and the ribs are hard, it is difficult to fit the bus bar members 3 within the groove portions in a firmly fitting state. Thus, there arises a problem that when the bus bar members 3 are not engaged by a particular engagement means, the close adhesion between both the bus bar members and the ribs can not be guaranteed and so abnormal sound such as rattling sound is generated due to the loose fitting state of the bus bar members 3.
Further, as shown in FIG. 11, generally, the bus bar wiring plate 1 is formed by laminating the insulating substrates 2 and the bus bar members 3 in plural stages. An insulating member 5 made of rubber etc. is sandwiched between the insulating substrate 2 of the upper layer and the insulating substrate 2 of the lower layer to press the bus bar members 3 of the lower layer through the insulating member 5, whereby the rattling phenomenon can be prevented and the insulating properties can be improved.
However, the bus bar wiring plate 1 can not be miniaturized nor lightened and further is limited in the improvement of the withstand voltage.
The invention is intended to eliminate the aforesaid problem of the conventional technique, and an object of the invention is to provide a bus bar wiring plate body for an electric coupling box which can improve insulating properties between bus bar members to prevent the generation of a leak current and also can miniaturize the size thereof.
To achieve the aforesaid object, there is provided a bus bar wiring plate body for an electric coupling box comprising:
a pair of pre-hardening epoxy resin plates with soft property having through holes; and
a plurality of bus bar members wired between the pair of pre-hardening epoxy resin plates, which respectively have tab shaped terminals protruding therefrom and passed through the through holes,
wherein the pair of pre-hardening epoxy resin plates and the plurality of bus bar members are heated and hardened to integrate the plurality of bus bar members in an electrically insulated state.
According to the bus bar wiring plate body for the electric coupling box thus configured, since the respective bus bar members are heated and hardened in a state being sandwiched between the respective pre-hardening epoxy resin plates, a single bus bar wiring plate body can be formed without providing a supporting plate etc. At the time of the heat pressing operation, the pre-hardening epoxy resin plates become fluid between the respective pre-hardening epoxy resin plates and also flow into engagement holes etc. formed at the respective bus bar members and thereafter heated and hardened. Thus, the rattling phenomenon of the respective bus bar members can be prevented and the insulating properties thereof can be improved, so that the leak current can be reduced and the bus bar wiring plate body can be miniaturized and light-weighted. that, preferably, the bus bar wiring plate body for an electric coupling box is characterized in that hardened epoxy resin plates with hard properties are laminated on the respective pre-hardening epoxy resin plates from outsides thereof, respectively, and heated and hardened to thereby integrate the respective pre-hardening epoxy resin plates, the respective bus bar members and the respective hardened epoxy resin plates.
According to the bus bar wiring plate body for the electric coupling box thus configured, since the insulation etc. of the respective bus bar members is covered by the respective hardened epoxy resin plates, the bus bar wiring plate body can be entirely enhanced in its strength.
Furthermore, the aforesaid problems can be obviated in a manner that, preferably, the bus bar wiring plate body for an electric coupling box is characterized in that a printed circuit board with hard property is laminated on at least one of the pre-hardening epoxy resin plates from outsides thereof and heated and hardened to thereby integrate the respective bus bar members and a circuit pattern formed on the printed circuit board in an insulated state.
According to the bus bar wiring plate body for the electric coupling box thus configured, since the circuit pattern is laminated on the respective bus bar members, the packaging density of the bus bar wiring plate body can be improved.
Furthermore, the aforesaid problems can be obviated in a manner that, preferably, the bus bar wiring plate body for an electric coupling box is characterized in that the tab shaped terminals formed by electing one end of the bus bar members are coupled to predetermined positions of the circuit pattern formed on the printed circuit board, respectively..
According to the bus bar wiring plate body for the electric coupling box thus configured, since the bus bar members are coupled to the circuit pattern formed on the printed circuit board, the bus bar wiring plate body can be made multifunctional.
Furthermore, the aforesaid problems can be obviated in a manner that, preferably, the bus bar wiring plate body for an electric coupling box is characterized in that the tab shaped terminals formed by electing one end of the bus bar members are respectively protruded as external coupling terminals through the through holes formed at least in the pre-hardening epoxy resin plate, and possibly also in the hardened epoxy resin plate.
The aforesaid object can also be achieved by a method of manufacturing a bus bar wiring plate body for an electric coupling box, said method comprising the steps of:
wiring a plurality of bus bar members between a pair of pre-hardening epoxy resin plates with soft properties; and
heating and hardening the plurality of bus bar members and the pair of pre-hardening epoxy resin plates to integrate the plurality of bus bar members in an electrically insulated state.
Regarding the above method, preferably, in said wiring step, a gap is formed between the plurality of bus bar members and the pair of pre-hardening epoxy resin plates.
Regarding the above method, preferably, the pair of pre-hardening epoxy resin plates are pressed toward the plurality of bus bar members during said heating and hardening step.
Regarding the above method, preferably, the method of manufacturing the bus bar wiring plate body further comprising, between said wiring step and said heating and hardening step, the step of:
disposing a pair of hardened epoxy resin plates so as to put the pair of pre-hardening epoxy resin plates therebetween.